On Edward's death, the King's Council (the Witenagemot) confirmed Edward's brother-in-law Harold, Earl of Wessex, as King. With no royal blood, and fearing rival claims from William Duke of Normandy and the King of Norway, Harold had himself crowned in Westminster Abbey on 6 January 1066, the day after Edward's death. During his brief reign, Harold showed he was an outstanding commander.

In September, Harald Hardrada of Norway (aided by Harold's alienated brother Tostig, Earl of Northumbria) invaded England and was defeated by Harold at the Battle of Stamford Bridge near York. Both Tostig and Harald Hardrada were killed in the battle. Hardrada's army had invaded using over 300 ships; so many were killed that only 25 ships were needed to transport the survivors home.

Meanwhile, William, Duke of Normandy (who claimed that Harold had acknowledged him in 1064 as Edward's successor) had landed in Sussex. Harold rushed south and, on 14 October 1066, his army of some 7,000 infantry was defeated on the field of Senlac near Hastings. Harold was hit in the eye by an arrow and cut down by Norman swords.

An abbey was later built, in 1070, to fulfil a vow made by William I, and its high altar was placed on the spot where Harold fell. The ruins of Battle Abbey still remain with a stone slab marking where Harold died.